The invention relates to an improvement in connectors utilized for joining together two separate entities, bodies or objects which may be subjected to a sudden pull, force or strain. The invention includes in particular an improvement in leashes, leads, lines and like connectors for restraining and controlling large animals. But it has a variety of other, generally similar, applications to line-like connectors, such as vehicle tow lines, tie-down lines for aircraft, tent guy ropes, mooring lines for boats, swing chains, expansible connectors for exercise equipment, and the like.
The invention especially is applicable to manually held leashes, leads or lines used when walking or exercising large animals, such as a horse or a large dog. which may tug vigorously or forcibly on the leash, or may suddenly pull, lunge or bolt, thereby severely yanking or jerking the leash. The shock of such sudden activity can be severe, and can result in painful injuries to the person holding the leash. Frequently, with a particularly large and strong animal, a sudden lunge or bolt can pull the leash from the grip of the person who is walking or otherwise controlling the animal.
Numerous attempts have been made to provide flexible or expansible leashes or leads for animals, such as dogs, for absorbing the shock of a sudden pull or jerk when the animal jumps, bolts or lunges. However, such prior devices do not appear to have been very effective in practical use, and apparently have received very little, if any, widespread usage. A problem inherent in such prior flexible or extensible animal leashes is the absence of any selectively controllable shock absorbing mechanism by which, in practical use, adjustments may be made to adapt the leash to the particular rigors of use to which it is exposed, such as size, temperament and type of animal. Samples of such prior devices are illustrated by the following U.S. Pat. Nos. 1,924,596, 2,275,701, 2,337,970, 2,737,154, 2,911,947 and 3,441,005.